The present invention relates to detergent compositions in non-particulate form that have a protective coating. More particularly, the invention relates to coated non-particulate detergent products e.g., tablet, block or bar, having a specially contoured surface which reduces the coating""s susceptibility to being chipped or broken away during manufacture, storage and handling.
Non-particulate detergents are an attractive alternative to granular or particulate forms of detergents from the standpoint of simplifying the dosing of such detergents for automatic laundry or dishwashing machines. Non-particulate detergents are usually supplied in the form of bars, tablets or briquettes and they not only prevent spillage of the detergent composition but also eliminate the need for the consumer to estimate the correct dosage of the detergent composition per wash. Non-particulate detergents minimize the contact by the consumer with the detergent.
In order to improve the hardness of a non-particulate detergent, such as a tablet, the tablets are occasionally encapsulated by a protective coating, which is broken when the tablet is immersed in water in the washing machine, thereby exposing the soft core which breaks up easily and rapidly, releasing the active ingredients into the wash solution. However, one problem frequently encountered with coated detergent tablets is that during manufacture, transportation, storage and handling, the coating can get chipped or broken away, especially around sharp edges or corners, by either rubbing against each other or against another surface. This not only reduces the structural integrity of the detergent tablet but also takes away from its appearance and aesthetics. Most consumers do not like to purchase a detergent tablet product which is chipped or has broken edges.
It is thus highly desirable to have a coated detergent tablet product having a surface configuration which reduce the coating""s susceptibility to chipping and fracture so that the coating remains adhered to the tablet during packaging, transport, storage and handling prior to eventual use.
The prior art is replete with methods of forming and coating tablets.
GB-A-0 989 683, published on Apr. 22, 1965, discloses a process for preparing a particulate detergent from surfactants and inorganic salts; spraying on water-soluble silicate; and pressing the detergent particles into a solid form-retaining tablet. Finally a readily water-soluble organic film-forming polymer (for example, polyvinyl alcohol) provides a coating to make the detergent tablet resistant to abrasion and accidental breakage.
EP-A-0 002 293, published on Jun. 13, 1979, discloses a tablet coating comprising hydrated salt such as acetate, metaborate, orthophosphate, tartrate, and sulphate.
EP-A-0 716 144, published on Jun. 12, 1996, also discloses laundry detergent tablets with water-soluble coatings which may be organic polymers including acrylic/maleic co-polymer, polyethylene glycol, PVPVA, and sugar.
The invention meets the needs above by providing a non-particulate detergent product including, a core formed by compressing a particulate material comprising a detersive surfactant and a builder. The core is compressed into a tubular configuration having a polygonal cross-section and a plurality of surfaces meeting to form a plurality of edges, thereby forming a contoured core, wherein at least one of the plurality of edges is chamfered. The non-particulate detergent product further includes a coating which substantially covers the contoured core.